WO2002032494A2

WO2002032494A2 - Multiple purpose catheter

Info

Publication number: WO2002032494A2
Application number: PCT/GR2001/000038
Authority: WO
Inventors: Christos Panotopoulos
Original assignee: Christos Panotopoulos
Priority date: 2000-10-19
Filing date: 2001-10-16
Publication date: 2002-04-25
Also published as: AU2001295815A1; GR1003723B; WO2002032494A3

Abstract

Multiple purpose catheter, which can be used for infusion, aspiration, biopsy, pressure monitoring and microdialysis, in humans, animals and biological material. These possibilities are conferred upon the catheter from different stylets and appropriate connnections. The microdialysis stylet can cooperate with any catheter which has analogous features and effectuate microdialysis.

Description

MULTIPLE PURPOSE CATHETER

This invention is about a catheter that can be used for infusion, aspiration, biopsy, pressure monitoring and microdialysis in humans, animals and biological material. Actually there are catheters, with one or multiple lumina, which are used in clinics and biological laboratories. Their functions are: the infusion of drugs and various liquids, the aspiration of liquid collections in the body or any biological material, pressure monitoring of body fluids and microdialysis. Microdialysis catheters consist of two concentric cylinders. On one side, the ends of these cylinders are covered by the same microporous membrane or grid, whose the size of the pores varies.

When the end of the catheter is placed in the extracellular space of a tissue and at the same time a fluid is infused from the inner cylinder towards the membrane or grid, the fluid will return through the space between the two cylinders, having exchanged substances and water with the extracellular fluid of the tissue.

The parameters that affect this exchange are the composition and concentration of substances in the fluid and in the extracellular space, as well as the speed that the fluid is passed through the cylinders. By analysing the fluid, after its return through the cylinders, we obtain information about the composition of the extracellular fluid of the tissue that the catheter was placed. Obviously this information will regard substances having a size small enough to pass through the pores of the membrane.

The most usual problems during the use of common catheters are their obstruction and the possibility of infection of the patient. Microdialysis catheters present rarely such problems.

Their membrane though, does not allow the exchange of substances with a size larger than the size of its pores, and limits substantially the microdialysis catheter^'s capacity to remove and supply fluids, as compared to a same diameter common catheter. Common catheters, having one or more lumina. can be used to aspirate or infuse a fluid, with a comparatively large fluidic supply, proportional to the size of their opening at the tip of the catheter. They lack however the ability, to supply crucial information on the composition of the extracellular fluid of the tissue, that the catheter is placed, as compared to the microdialysis catheters, that do so. in a continuous, easy and painless way.

An example, chosen from the routine clinical practice, is the intravenous placement of a catheter, for blood sampling and drug or fluid delivery. Common catheters, can be used to sample volumes of whole blood from a patient, or to deliver large volumes of fluids; in practice however, for reasons of result credibility as well as catheter^'s obstruction and contamination risk avoidance, blood sampling is performed only once, immediately after the vein puncture and before the intravenous supply of fluid.

On the other hand, microdialysis catheters actually used, cannot aspirate whole blood. They can aspirate fluids composed of lower than 20000 molecular weight substances and infuse fluid volumes up to 300μlt per hour only, but they have not obstruction and contamination problems and they allow continuous and painless patient monitoring . The present invention aims to create a catheter, that combines the functions of infusion, aspiration, biopsy, pressure monitoring and microdialysis, without the afore-mentionned restrictions and complications of existing microdialysis and common catheters. These characteristics originate from different stylets and appropriate connections of the catheter.

This catheter consists of the parts described below with numbers which refer to the drawings attached. First is the main catheter part. Second is the introduction and biopsy stylet part. Third is the microdialysis stylet part. The main catheter is a tube made of plastic or any other material with appropriate characteristics for the intended use. The distal end of the catheter allows the hermetic fit of the internal and external stylets. The proximal end of the catheter has two openings: a central opening, for the introduction and hermetic fit of an internal stylet or a syringe or a connecting tube, and a side opening for hermetic fit of a svrinse or a connecting tube. Drawing 1 shows the distal end 1.1, which is conical. The proximal end 1.2 has the central 1.3 and side 1.4 openings, which can be of any form that guarantees the hermetic fit of the connections. For special uses, the main catheter may have more than one lumen, for example an additional lumen with a balloon at its tip, that allows the catheter's wedging in the tissue of interest. The main catheter can infuse, aspirate and monitor body fluids^' pressure ( when properly connected to a vertical column of liquid ). Additionally, with the appropriate stylets, it can be used for biopsy and microdialysis.

The catheter needs a stylet of introduction and biopsy, suitable for the tissue of interest. It can be made of metal or any other material, fit for the intended use. The shape of the stylet, depends on the need or not, to combine biopsy along with introduction. When there is no need for a biopsy, a solid or tubular simple stylet, with sharp or blunt tip according to the tissues to be traversed, is preferred. When there is a need for biopsy, one can use the appropriate biopsy catheter as a stylet for the main catheter. In both cases, it is advisable to start the catheter^'s introduction with a sharp- tipped stylet and continue with a blunt-tipped one, otherwise one risks damage to the main catheter^'s wall. The stylet either surrounds (external stylet), or is surrounded by the main catheter (internal st let). The drawings show examples of introductory and biopsy stylets. Drawing 2 shows a simple, tubular, sharp-tipped, internal, metallic sty let, suitable for transdermal puncture of a blood vessel. Blood enters its tip (2.1 ) and reaches the transparent chamber 2.2, through a fιlter(2.3). verifying the stylet^'s entrance into the vessel. 2.4 is the stylet^'s part that fits to the main catheter^'s proximal part. Drawing 3 shows a blunt-tipped, internal, metallic biopsy stylet, suitable for stereotactic brain biopsy, following cranioanatresis and incision of the meninges. It consists of an external part, with an opening at it^'s distal end 3.1 and a proximal end 3.2 that fits to the proximal end of the main catheter, as well as of an internal part, with an opening 3.3 and a proximal end 3.4 which can be connected to a svringe or a cover 3.5. A side view of the distal end of this stylet is shown at 3.6.

During stylet introduction to the brain, the openings are facing opposite directions. After introduction, one allows the coincidence of the openings by rotating the internal part. Brain tissue then enters the opening and one cuts it off by rotating the internal part to its initial position.

Drawing 4 shows a simple, solid, blunt-tipped, internal, metallic stylet, which combined with the plastic, external, tubular, blunt-tipped, simple stylet shown at drawing 5, allows the intraperitoneal positioning of the main catheter, after skin incision. The plastic stylet is removed, ifter having guided the main catheter into the tissue of interest, by splicing upon retraction along the 5.1 line, starting from 5.2 proximal end. Afterwards the internal solid stylet is removed. The microdialysis stylet (drawings 6. 7, 8, 9) is made of plastic or any other appropriate material. It consists of the microdialysis membrane or grid (6.1 , 7.1 , 9.1 ). its base(6.2, 7.2, 9.2) and the catheter(6.3, 7.3, 8.3, 9.3 ). which can be efferent or afferent by choice, with or without introductory stylet (7.4, 8.4, 9.4). The base of the membrane or grid, is wedged hermetically in the opening (6.5, 7.5. 9.5) of the main catheter (6.6. 7.6. 8.6, 9.6), effectuating microdialysis, since fluid passes imperviously, membrane or grid exchanges apart, from the efferent or afferent internal catheter (6.3, 7.3. 8.3, 9.3), to the. afferent or efferent respectivelly, external main catheter (6.6. 7.6, 8.6, 9.6), through openings of internal catheter^'s tip (6.7, 7.7, 9,7) and openings of the membrane^'s or grid^'s base (7.9. 9.9). The membrane^'s or grid^'s base and the internal catheter^'s tip. can have any shape guarantees hermetic fit and easy partition.

The catheter of the microdialysis stylet (6.3. 7.3, 8.3, 9.3). has a distal end that allows passage of fluids (6.7, 7.7. 9,7) and connection with the membrane or grid (6.8. 7.8). or with the membrane^'s or grid^'s base (9.8). The proximal end of the microdialysis stylet (6,8, 8.8). permits a secure, hermetic fit to the central opening ( 1.3. 6.9. 8.9) of the proximal end of the main catheter. as well as to the proximal end (8.5) of the stylet (8.4) of the microdialysis stylet^'s catheter (8.3 ). or any other connection (6.4). like a pump which supplies liquid through a fitting tube. The side opening of the main catheter 6, A , is shown to be imperviously connected to a tube, that ends to a microdialysis collection vial. Arrows indicate the liquid^'s direction during microdialysis. when a microdialysis pump is connected to the central opening. A microdialysis stylet could enable any existing common catheter to perform microdialysis. prov ided there is correspondence of shapes and sizes of distal and proximal ends, that permit hermetic fit and appropriate connections. Catheter with a proximal end opening ( 10.1 ). can be combined with a suitable microdialysis sty let through appropriate connection ( 10.2) . It is obvious, that one can place the catheter of drawing 1 into a vessel, with the help of the stylet of drawing 2. After the retraction of the stylet 2, one can perform blood sampling through the 1.4 or the 1.3 opening, and after that one can introduce the microdialysis stylet and perform microdialysis. Based on microdialysis results, one could administer liquids and drugs, by retracting the microdialysis stylet and connecting 1.4 or 1.3 with an infusion pump. After infusion of liquids and drugs is terminated, one can introduce the microdialysis stylet and perform microdialysis again. New results can be compared to the results of a new blood sampling from catheter 1 , and so on. Catheter 1 , if properly connected to a vertical liquid column, can monitor pressure inside a vessel. Stylet 3 and catheter 1 combined, permit, after performing a biopsy, to administer drugs and monitor biochemical changes at biopsy site, by the introduction of a microdialysis stylet properly connected to a suitable pump and collecting vials, after stylet 3 retraction. Analogous examples, concerning intraperitoneal, intramuscular and other uses of the catheter, are easy to conceive. There are obviously respective differences, concerning shapes and sizes of stylets and main catheters.

Claims

1 , Multiple purpose catheter, having one or multiple lumina. of single or multiple use. which consists of one main catheter ( 1 ). with one. at least . central ( 1.3 ) and one. at least, side ( 1.4) opening at its proximal end ( 1.2), properly shaped in order to permit the introduction and hermetic fit of stylets, syringes and connecting tubes, and a distal end (1.1), properly shaped in order to permit the hermetic fit of internal and external stylets. The catheter^'s form, dimensions, construction materials and procedure, are modified accordingly, in order to suit the intended use. in various body tissues or biological material. The catheter permits the functions of infusion, aspiration, biopsy, pressure monitoring and microdialysis. said catheter is characterized by the appropriate connections and stylets (3, 6. 7, 8. 9). Microdialysis stylets (6. 7, 8, 9), are made of plastic or any other appropriate material and consist of a microdialysis membrane or grid (6.1 ,

7. L 9.1). its base(6.2. 7.2, 9.2), a catheter(6.3. 7.3. 8.3. 9.3),^" with or without introductory stylet (7.4, 8.4, 9.4), and its base(6.8, 8.8). The membrane^'s or grid^'s base and the internal catheter^'s tip. can have any shape permits their hermetic fit and easy partition. The microdialysis stylet^'s catheter form (6.3. 7.3. 8.3, 9.3). permits fluid passage (6.7, 7.7,

9.7) and connection with the membrane or grid (6.8. 7.8), or their base (9.8). at its distal end. and allows hermetic fit with its stylet, connecting tube and the main catheter at its proximal end (6.8. 8.8).

2, Microdialysis stylet, according to claim 1 , which is characterized in that combined to any catheter with appropriate features, permits microdialysis effectuation.

3. Catheter, according to claim 1. which is constructed by proper joining or gluing together of a microdialysis stylet (6.7.8.9) and a main catheter ( 1 ). and is used for microdialvsis.